Synthesis, photophysical properties and sugar-dependent in vitro photocytotoxicity of pyrrolidine-fused chlorins bearing S-glycosides

Eight S-glycosylated 5,10,15,20-tetrakis(tetrafluorophenyl)porphyrins (1a′, 1b′, 1a and 1b (a: S-glucosylated, b: S-galactosylated)) and their 1,3-dipolar cycloadducts, i.e. chlorins 2a′, 2b′, 2a and 2b were prepared by nucleophilic substitution of the pentafluorophenyl groups with S-glycoside. These photosensitizers were characterized by ¹H, ¹³C and ¹⁹F NMR spectroscopies and elemental analysis. The photocytotoxicity of the S-glycosylated photosensitizers and the parent porphyrin (1) and chlorin (2) was examined in HeLa cells. Photosensitizers 1, 2, 1a′, 1b′, 2a′ and 2b′ showed no significant photocytotoxicity at the concentration of 0.5 μM, while the deprotected photosensitizers 1a, 1b, 2a and 2b were photocytotoxic. The strong inhibition by sodium azide of the photocytotoxicity of these photosensitizers suggested that ¹O₂ is the main mediator. The S-glucosylated photosensitizers 1a and 2a showed higher photocytotoxicity than S-galactosylated 1b and 2b, respectively. The cellular uptake of 1a and 2a increased up to 24 h, while that of 1b and 2b was saturated by 12 h.     

Paclitaxel‐Loaded Stabilizer‐Free Poly(D,L‐lactide‐co‐glycolide) Nanoparticles Conjugated with Quantum Dots for Reversion of Anti‐Cancer Drug Resistance and Cancer Cellular Imaging

We prepared the PLGA‐loaded anti‐cancer drug and coated it with quantum dots to make it a dual‐function nanoparticles, and analyzed its potential use in cellular imaging and curing cancers. Two cancer cell lines, paclitaxel‐sensitive KB and paclitaxel‐resistant KB paclitaxel‐50 cervical carcinoma cells, were the relativistic models for analysis of the cytotoxicity of free paclitaxel and paclitaxel‐loaded PLGA conjugated with quantum‐dot nanoparticles. The paclitaxel‐loaded PLGA conjugated with quantum dots nanoparticles were significantly more cytotoxic than the free paclitaxel drug in paclitaxel‐resistant KB paclitaxel‐50 cells. This might have been because the cancer cells developed multi‐drug resistance (MDR), which hampered the action of free paclitaxel by pumping its molecules to extracellular areas. Addition of verapamil, a P‐glycoprotein inhibitor, reversed the MDR mechanism and significantly reduced KB paclitaxel‐50 cell viability. As a result, KB paclitaxel‐50 was highly associated with MDR on the cell membrane. The cytotoxicity results indicated that PLGA nanoparticles served as drug carriers and protected the drugs from MDR‐accelerated efflux. Combined quantum dots with PLGA nanoparticles allowed additional functionality for cellular imaging.     

Analysis of E. coli soluble proteins by non‐denaturing micro 2‐DE/3‐DE and MALDI‐MS‐PMF

Escherichia coli (strain K‐12)‐soluble proteins were analyzed by nondenaturing micro 2‐DE and MALDI‐MS‐PMF. The reported conditions of nondenaturing IEF in agarose column gels [Jin, Y., Manabe, T., Electrophoresis 2009, 30, 939–948] were modified to optimize the resolution of cellular soluble proteins. About 300 CBB‐stained spots, the apparent molecular masses of which ranged from ca. 6000 to 10 kDa, were detected. All the spots on two reference 2‐DE gels (one for wide mass range and one for low‐molecular‐mass range) were numbered and subjected to MALDI‐MS‐PMF for the assignment of constituting polypeptides. Most of the spots (310 spots out of 329) provided significant match (p<0.05) with polypeptides in Swiss‐Prot database and totally 228 polypeptide species were assigned. Activity staining of enzymes such as alkaline phosphatase and catalases was performed on the 2‐DE gels and the locations of the activity spots matched well with those of the MS‐assigned polypeptides of the enzymes. Most of the polypeptides with subunit information in Swiss‐Prot (119 polypeptides as homo‐multimers and 25 as hetero‐multimers out of the 228), such as pyruvate dehydrogenase complex which is composed of three enzymatic components, were detected at the apparent mass positions of their polymers, suggesting that the proteins were separated retaining their subunit structures. When a nondenaturing 2‐DE gel was vertically cut into 2 mm strips and one of the strips was subjected to a third‐dimension micro SDS‐PAGE (micro 3‐DE), about 190 CBB‐stained spots were detected. The assignment of the polypeptides separated on the 3‐DE gel would further provide information on protein/polypeptide interactions.     

Synthesis and Characterization of CdTe@CdS Quantum Dots Layered on Silica Nanoparticles

CdTe@CdS quantum dots, cationic polyelectrolyte poly-diallyldimethylammonium chloride, and anionic polyelectrolyte polyacrylic acid were assembled on the surface of silica nanoparticles based on the electrostatic layer-by-layer self-assembly to prepare fluorescent composite nanoparticles. Transmission electron microscopy showed that the particles had a uniform size distribution (approximately 70 nm) and good monodispersity. The fluorescence shielding effect of the silica shell was reduced and the assembled quantum dots were well protected by the sandwich structure. The nanoparticles provided strong fluorescence, high stability for storage, and low photobleaching and leakage. Furthermore, they possessed high fluorescence stability and high-concentration staining for cytoplasm, which enabled them to be used for sensitive cellular imaging analysis. Because of the presence of numerous carboxyl groups, they have potential application for biolabeling and bioanalysis.     

铈和钆对体外培养正常二倍体细胞的作用

采用同位素示踪、细胞周期分析和组化等技术，研究Ｃｅ３＋和Ｇｄ３＋对动物正常二倍体细胞的生物学作用。结果表明，Ｃｅ３＋和Ｇｄ３＋仅在一个狭窄的剂量范围（１×１０－６～１×１０－５ｍｏｌ／Ｌ）可促进正常二倍体细胞增殖，有明显的剂量—效应关系。Ｃｅ３＋和Ｇｄ３＋在高浓度时（１×１０－３ｍｏｌ／Ｌ），对细胞具有毒性，可使细胞坏死、增殖缓慢并诱导细胞凋亡。     

Proteomic analysis of cellular soluble proteins from human bronchial smooth muscle cells by combining nondenaturing micro 2DE and quantitative LC‐MS/MS. 2. Similarity search between protein maps for the analysis of protein complexes

Human bronchial smooth muscle cell soluble proteins were analyzed by a combined method of nondenaturing micro 2DE, grid gel‐cutting, and quantitative LC‐MS/MS and a native protein map was prepared for each of the identified 4323 proteins [1]. A method to evaluate the degree of similarity between the protein maps was developed since we expected the proteins comprising a protein complex would be separated together under nondenaturing conditions. The following procedure was employed using Excel macros; (i) maps that have three or more squares with protein quantity data were selected (2328 maps), (ii) within each map, the quantity values of the squares were normalized setting the highest value to be 1.0, (iii) in comparing a map with another map, the smaller normalized quantity in two corresponding squares was taken and summed throughout the map to give an “overlap score,” (iv) each map was compared against all the 2328 maps and the largest overlap score, obtained when a map was compared with itself, was set to be 1.0 thus providing 2328 “overlap factors,” (v) step (iv) was repeated for all maps providing 2328 × 2328 matrix of overlap factors. From the matrix, protein pairs that showed overlap factors above 0.65 from both protein sides were selected (431 protein pairs). Each protein pair was searched in a database (UniProtKB) on complex formation and 301 protein pairs, which comprise 35 protein complexes, were found to be documented. These results demonstrated that native protein maps and their similarity search would enable simultaneous analysis of multiple protein complexes in cells.     

Guanidinoamidized linear polyethyleneimine for gene delivery

Guanidine was introduced to low molecular weight linear polyethyleneimine(LPEI) via amide groups, to explore the effect of both guanidine degree and pendant chain length on its transfection behavior. The resulting guanidinoamidized LPEIs(GLPEIs) could dramatically reduce LPEI's toxicity, enhance its DNA-packaging capability, cellular uptake and therefore transfection efficiency. These polyplexes were taken up very efficiently via caveolae-mediated endocytosis and their transfection efficiencies in ovarian cancer cells were significantly improved compared to native LPEI10 k polyplexes. Among these GLPEIs, LPEI-C3-G100 showed higher DNA affinity even than LPEI25 k and the highest transfection efficiency, probably due to the optimization of polymer chain flexibility. Of notice, LPEI-C3-G100 polyplexes could more effectively accumulate into cytoplasm than LPEI25 k, although the transfection efficiency of LPEI-C3-G100 polyplexes was not superior to that of LPEI25 k polyplexes, which would be probably attributed to the more efficient release of LPEI25 k polyplexes than LPEI-C3-G100 polyplexes in the cytoplasm.     

Influence of emulsification process on structure–properties relationship of highly concentrated reverse emulsion-derived materials

Water-in-Oil high internal phase emulsions (HIPEs) whose continuous phase is polymerizable gave access to highly porous polymeric materials (polyHIPEs). These emulsions were prepared with a laboratory-made homogenizer whose shear frequency and time could be varied to study the influence of the emulsification conditions on the polyHIPEs morphology. Intensive and/or long shear induced a reduction of the cell and connection diameters without any modification of the material global porosity. The mechanical properties were evaluated by estimating the Young’s modulus from compression tests. The mechanical behavior was analogous for all materials possessing a characteristic polyHIPE structure, even if cell sizes were different between samples.     

微流控芯片中细胞动态胞吞二氧化硅纳米颗粒的研究

研究了用微流控芯片在体外模拟人体血液流动状态下细胞胞吞二氧化硅纳米粒子的方法和特性. 通过调节储液池的液面差, 使细胞从微通道入口流入并在通道内沉积贴壁生长. 将含有贴壁细胞的微流控芯片放入37 ℃/体积分数5%CO₂的培养箱中, 使细胞培养液连续流过贴壁细胞. 培养24 h后, 在流动的培养液中加入作为荧光标记物的500 nm 粒径的掺杂有异硫氰酸荧光素(FITC)的二氧化硅微球(MSN), 继续培养6 h后, 用荧光显微镜测定细胞胞吞二氧化硅纳米粒子后的荧光强度, 考察了不同流速下细胞对二氧化硅微球摄入量的影响. 结果表明, 在动态条件下, 细胞对二氧化硅微球的吞噬量明显下降, 当流速从0.022 mm/s 增加至0.74 mm/s时, 吞噬量从静态测得值的74.7%下降至7.1%.     

Pattern memory analysis based on stability theory of cellular neural networks

In this paper, several sufficient conditions are obtained to guarantee that the n-dimensional cellular neural network can have even (?2ⁿ) memory patterns. In addition, the estimations of attractive domain of such stable memory patterns are obtained. These conditions, which can be directly derived from the parameters of the neural networks, are easily verified. A new design procedure for cellular neural networks is developed based on stability theory (rather than the well-known perceptron training algorithm), and the convergence in the new design procedure is guaranteed by the obtained local stability theorems. Finally, the validity and performance of the obtained results are illustrated by two examples.